Two-year corneal crosslinking results discussed

At this year’s annual meeting, long-term clinical outcomes of a corneal crosslinking study will be presented
In the U.S., corneal crosslinking clinical studies have just begun, but overseas some of the longer-term results are beginning to trickle in. One such study, conducted in Israel, will be presented on April 10 during the annual ASCRS conference. The study, “Clinical and corneal biomechanical changes after CXL with riboflavin and UV irradiation in patients with progressive keratoconus: Results after 2-year follow-up,” is being presented by David Zadok, M.D., department of ophthalmology, Assaf Harofeh Medical Center, Tel Aviv University, Ramat Aviv, Israel.
He and colleagues Yaniv Barkana, M.D., and Yakov Goldich, M.D., prospectively enrolled 14 eyes of 14 patients with progressive keratoconus and treated them with corneal crosslinking after corneal de-epithelialization. Patients were assessed preoperatively, and at week 1 and months 1, 3, 6, 9, 12, and 24 after treatment. Uncorrected visual acuity improved over the 24 months, but was not statistically significant. Best corrected visual acuity, however, reached a statistically significant improvement at both months 12 and 24, improving from a mean baseline of 0.21 logMAR to 0.11 and 0.14, respectively.
“A lack of an observed improvement in UCVA can be explained in that, despite changes in keratometry and reduced ectasia, axial length also changed and negated the effects,” Dr. Zadok told EyeWorld in an email interview. “Spectacle BCVA, on the other hand, did improve significantly because the myopia component could be corrected. At the time, there hadn’t been many studies that showed long-term changes in visual acuity following corneal crosslinking, so we did not expect improvement in visual acuity. We can attribute it to the improvement/decrease in ectasia.”
A further analysis showed stable corneal thickness (from a mean baseline of 461 µm to 466 µm at 24 months), and no significant changes in endothelial cell density.
“The results of this, and other studies from around the globe, support corneal crosslinking as being a first-line treatment for patients diagnosed with keratoconus,” said William B. Trattler, M.D., director, Cornea, Center for Excellence in Eye Care, Miami, commenting on the relevance of the findings. “As clinicians, identifying and treating the condition sooner will prevent the keratoconus from becoming more advanced.”
When the study began, Dr. Zadok said his group expected the stabilization of keratometry, “but we were surprised that the stabilization was maintained throughout the study period (at least 2 years), with gradual improvement in visual acuity and even continued decrease in keratometry, even between the 1- and 2-year time points.”
Another unique finding, he said, was an ongoing increase in axial length, “which implies involvement of scleral collagen in keratoconus.”
Adverse events were minimal, with one patient having persistent corneal stromal haze. Dr. Zadok opted to observe, and said a more recent follow-up indicated the scar “has been fading with time without any treatment.”
Dr. Trattler said that may be a key point for clinicians to remember. “Just as with procedures like PRK where a large epithelial defect is created, there is a small but real risk of infection and/or delays in epithelial healing. It is therefore important to evaluate patients preoperatively for dry eye—and treat if present. One other consideration is that patients with keratoconus typically have steep, irregular corneas. A standard bandage contact lens may interrupt epithelial healing due to rubbing at the apex of the cone, which can lead to delays in epithelial closure,” he said.
For clinicians, Dr. Zadok said the procedure “appears to be safe” and “does not cause damage to the corneal endothelium and central retina.”

Editor’s note: Drs. Zadok and Trattler have no financial intersts related to their comments.

Contact information

Zadok: +972 50 758-7348, davzadok@gmail.com
Trattler: 305-598-2020, wtrattler@gmail.com